I think maybe a few classic Sarah Janes, given the fact she has her own show now.
Also Kamelion, despite being a kind of lame classic character, would look kind of cool as a figure in his robot mode. (Although arguably the Planet of Fire Master *is* Kamelion!)
I wonder, however, why there are relatively few companion figures with the exception of Captain Jack and Martha. There's only one Donna(Her Planet of the Ood coat), one Amy, and only two Roses. I've heard apparentally Billie Piper was upset about her likeness on both her figures, hence no more Roses.
I wonder if we'll get a Rory figure next year. Maybe in Auton form to make it more appealing (After all, the only Mickey we got was "action" Mickey from Doomsday).